Selective repairing process for barrier layer

Abstract

A selectively repairing process for a barrier layer is provided. A repair layer is formed by chemical vapor deposition using an organosilicon compound as a precursor gas. The precursor gas adsorbed on a low-k dielectric layer exposed by defects in a barrier layer is transformed to a porous silicon oxide layer has a density more than the density of the low-k dielectric layer.

What is claimed is: 
     
       1. A method of repairing defects in a barrier layer, comprising:
 forming a damascene opening in a dielectric layer on a substrate, wherein a surface of the dielectric layer has free hydroxyl groups; 
 forming a barrier layer on the dielectric layer to cover inner surfaces of the damascene opening, wherein the barrier layer is discrete; and 
 depositing a repair layer on the dielectric layer exposed by defects in the barrier layer by chemical vapor deposition using an organosilicon as a precursor gas, wherein the organosilicon has a chemical formula of (CH 3 ) 3 Si—X, and X is a leaving group. 
 
     
     
       2. The method of  claim 1 , wherein the dielectric layer has a dielectric constant smaller than a dielectric constant of silicon dioxide. 
     
     
       3. The method of  claim 2 , wherein the dielectric layer is fluorine-doped silicon dioxide, carbon-doped silicon dioxide, porous silicon dioxide, porous carbon-doped silicon dioxide, hydrogen silsesquioxane, or methylsilsesquioxane. 
     
     
       4. The method of  claim 1 , wherein the barrier layer is made from a metal containing Co, Ru, Ta or any combinations thereof, or a conductive ceramics, which is tantalum nitride, indium oxide, copper silicide, tungsten nitride or titanium nitride. 
     
     
       5. The method of  claim 1 , wherein the organosilicon is a silane, silazane, or a siloxane. 
     
     
       6. The method of  claim 5 , wherein the silane comprises (CH 3 ) 3 Si—H. 
     
     
       7. The method of  claim 5 , wherein the silazane comprises (CH 3 ) 3 Si—N(C 2 H 5 ) 2  or [(CH 3 ) 3 Si] 2 —NH. 
     
     
       8. The method of  claim 5 , wherein the siloxane comprises (CH 3 ) 3 Si—O(CO)CH 3 . 
     
     
       9. A method of forming a damascene structure, comprising:
 forming a damascene opening in a dielectric layer on a substrate, wherein a surface of the dielectric layer has free hydroxyl groups; 
 forming a barrier layer on the dielectric layer to cover inner surfaces of the damascene opening, wherein the barrier layer is discrete; 
 depositing a repair layer on the dielectric layer exposed by defects in the barrier layer by chemical vapor deposition using an organosilicon as a precursor gas, wherein the organosilicon has a chemical formula of (CH 3 ) 3 Si—X, and X is a leaving group; 
 forming a seed layer on the repair layer and the barrier layer; 
 forming a metal layer on the seed layer to fill in the damascene opening; and 
 removing an upper portion of the metal layer, the seed layer, the barrier layer and the dielectric layer to form a metal interconnect in the damascene opening. 
 
     
     
       10. The method of  claim 9 , wherein the dielectric layer has a dielectric constant smaller than a dielectric constant of silicon dioxide. 
     
     
       11. The method of  claim 9 , wherein the barrier layer is made from a metal containing Co, Ru, Ta, or any combinations thereof. 
     
     
       12. The method of  claim 9 , wherein the metal the barrier layer is made from a conductive ceramics, which is tantalum nitride, indium oxide, copper silicide, tungsten nitride, or titanium nitride. 
     
     
       13. The method of  claim 9 , wherein the organosilicon is a silane, silazane, or a siloxane. 
     
     
       14. The method of  claim 13 , wherein the silane comprises (CH 3 ) 3 Si—H. 
     
     
       15. The method of  claim 13 , wherein the silazane comprises (CH 3 ) 3 Si—N(C 2 H 5 ) 2  or [(CH 3 ) 3 Si] 2 —NH. 
     
     
       16. The method of  claim 13 , wherein the siloxane comprises (CH 3 ) 3 Si—O(CO)CH 3 . 
     
     
       17. The method of  claim 9 , wherein the seed layer is made from Cu, Co, Al, Ag, or any combinations thereof. 
     
     
       18. The method of  claim 9 , wherein the metal layer made from copper. 
     
     
       19. The method of  claim 1 , wherein the repair layer has a porosity less than 30% and a pore size smaller than 20 Å.